Coated welding rod



Patented Mar. 2, l948 GOATED WELDING ROD ilohann jlliedrich vFast, nflm'iN therlauds,

Q "assignor to Hartford National Bank and "Trust =7 "companyffiart'ford,Comm, as trustee Nofnrawing r Application January 12!), .1943, Be-

.riaTNo; 475L002. In "the Netherlands 'March Section 1,;-Pnblic.Law 69D,i-August .8. 1946 24119111; expires March 15. 19 61 .7 :It; is 1:11pm:that fin ie'lectrlc arc welding :by means :of 4a weldingrmireiconsisting of iron or an ironwiallloy zthe are may sometimes :becomeextinguished. "Particularly in :the absence or a slag forming:coatingsthis :phenomenon, besides another annoying." phenomenon vviz.so-called fluttering ot athe arc; may make its appearance. When makinguse of :a zsla'gsforming coating in whichscase'an alkalineeart'hu-compound was often used; ;one;.;succeeded :in: many casessatisfactorily to avoid the said troublesome phenomenon of extinction.:Inithe.rsiurtherxxieveiopment :of the welding technique the:requirementssimposejd ion the: quality -of' izhewveld weresteadilyraised, more par 'ticuiarly inemeclianical' respect; gtowhich "thecomposition of the slag-"forming coatinghad to be fcaccommodated. IfInmany cases it "appeared that: the occurrence ef extinctionwasxpromoted thereby; whence, iteis oiimportance in such cases13075112316 ran "expedient for counteracting the :extinction' Thepresent invention is concerned with':this problem. ilfhuspit does notinclude coated weldingrods, with which the phenomenon of:extinctionwwithout malcmg "use of the invention does not occur andwhich, therefore, iaill beyond the :scope :of the present exclusive"rights.

In the-present case a'typeo't welding rod is can'- sidered to be notliable to extinction it the phe nomen'on :01 extinction does not occur-at all in carrying outthe welding operation with five 40f these rcds,having a IGHQth -OI Q LbOHUAE) cm. Zby means of a-transfomner having anopen circuit voltage -o! 55 110 160.

fine loeourrenceof extinction is acted .upon' by' the tcompos'ition ofthe is'lag iorming mass and in addition day the :open' circuit voltage:of the apparatus-used "in :we'lding (welding transformer or weldingrectifier? it-being pointed out 'that it is obiectionable to preventextinction "by "raising the open circuit voltage, particularly T011account (if-the danger wv-l'ii'ch: may he -incurred thereby.

viii-respective of the floss. of time involved by the repeatednceurrence{of extinction, this may also aIiIect the -envisaged quality of'eitheweld.

, Pairticularly when -makingwuse :of alternatin currentiextinctionmay-vcccur; which-is probably related withthe periodicchamgeaoffliirection :cf the eleotrlc 'cur'rent, i1 owing "to zwhichfthe arc is interrupted. :many times a r-sec'ond. Naturally, theexpression"to: zextinguisli does notxinclude these periodicinterruptions. The inverrtion purports to counteract the textinc'ti'onin f welding 'by :means'aof :coated' welding rods having a 'core'consisting ofvi-ron nor :an :iron alloy (containing imore 15.01% ofilton) in which we succeed, according to the invention;

bymaking'nise otmagneslumlin its metallic form as an auxiliary material.

- "1' Claims. {01;2151-6).

tion :procures .zan improvement also in regardto the so-calledstarting-up ofxthe arc, 1.8. that an arc canzberstruck more easily andswiftly between the piecerotwnrk and the weldingirod.

"fl-he .inagnesium maybe used in the. form of an .:a1loy,:for:instanceas as magnesium-aluminum allrmwhich ofiers'thezadvantage of beingcheaply obtainable .in the formpf waste .of articles made from thisalloy.

1 ilnscneexecutional example of the :inventionthe magnesium is unitedwith the'iron or the iron alloy of the core of atweldingrod, forinstance alloyedwith this metal'xor incorporated in a :hol-

low "core.

inthe11ast-mentionedumanner:the:risk of undesired reactions :between themagnesium and the remainder ofcthe coating masspwhieh is still moist,is: smaller.

1 :As has'..a-1r.eady been'rpointed oatabovepthe invention .is .ofrparticularriinportance when the "attempts are directed to a weldhaving-excellent properties, particularly a great match shocktoughnessfinwhich case athexuser is likely to impc'seihigh :requirementsalso :in '-.other respects,

1 inter :alia insregard .to extinction.- A slag formme mass for suchpurpose, which is especially used asiafl-coatingzfor highgrade weldingro havmgxandron :core or :a. core -cons;isti:ng of .an lron-ei1loyzcontaining more than. of iron) enerally contains a .zreducing'metalsuch as terroemanganese, :iierro-silicon,term-titanium, llon powder :orthe like. :In preparingsuch a sla forming massicffluoridepmoreparticularly calcium-fluoride is .oftenused which has -a--de t rimentalsheet on the extinct-ion and in which The use of the inveni casezthe ofthe-invention is particularly advantageons. V V

Thusrrfcrinstance;ithas nwned out i-n-electricarc welding Joy means oisuch welding rods turnished -with a slag iorming coating which:besides':-neducing term-alloys also contains alkaline earth carbonate,water'glass, highly refractory silicates, iron "oxides or, forinstance,alkaline earth carbonate, water calcium fluoride, that. :the annoying:extinction when .making use of a welding transformer having an opencircuit voltage of say about 60, is counteracted and even practicallyentirely prevented by the presence of a few percent by Weight ofmagnesium or of the magnesium alloy commercially known under theregistered trade mark "Electron" (containing 90 or more than 90 per centby weight of magnesium) in the form of powder in the coating.

This may be better understood by pointingout, that a quantity of about 2to per cent by weight of the coating permits the extinction to beprevented, if the magnesium or the said magnesiumaluminium alloy ismixed with the coating forming slag, whereas about 0.5 to 3 per cent. byweight of the coating is sufficient, if the metal core is first providedwith a powder layer of magnesium or of the magnesium alloy, whereuponthe slag forming mass is applied.

To be complete it is stated that a coating for welding rods has alreadybeen described, for instance in British Patent Specification 144,333,which contains magnesium, which serves to protect the core metal of thewelding rod during the welding operation against the action of theoxygen of the air.

. 4 comprising a core consisting of a metal' selected from the groupconstituted by iron and iron alloys containing at least about 50 percentof iron,

a slag-forming coating on said core, a reducing agent in said coatingconsisting of a suficient percentage of material other than magnesium"to prevent oxidation of the iron metal during welding, and an arc,preserving agent consisting .of at least about 90'percent of magnesiuminprevent oxidation of the iron metal during weld= According to theinvention the attempts are directed to the purpose outlined above, whichis entirely difierent therefrom, to counteract the occurrence ofextinction in welding by means of coated welding rods having a coreconsisting of iron or an iron alloy, and furthermore the exclusiverights accruing from the invention are ing, and an arc preserving agentconsisting of at least about 90 per cent of magnesium incorporated insaid coating in an amount of from about 2 to about 5 per cent by weightof the coating, for preventing extinction of the arc during welding. 5.A welding electrode for electric arc weldin comprising a core consistingof a metal selected from the group constituted by iron and iron alloyscontaining at least about 50 per cent of iron, a slag-forming coating onsaid core, a reducing agent in said coating consisting of a sufficientpercentage of material other than magnesium to prevent oxidation of theiron metal 'during I welding, and an arc preserving agent consisting ofat least about 90 per cent of magnesium inhighly diluted dispersion, sothat this coating accordingly produces such a. thin layer on the weldthat, according to the said patent specification it cannot be termedslag. The invention is different from these particularly coated weldingrods in that use is made of a slag forming coating, such as can beprovided by pressing for instance, and which forms in the usual way acoherent layer of slag melted together on the weld and which, therefore,is termed forming slag hereinbefore.

I claim:

. l. A welding electrode for electric arc welding comprising a coreconsisting of at least about 50 per cent of iron, a slag-forming coatingon said core, a reducing agent in said coating consisting of a sumcientpercentage of material other than magnesium to prevent oxidation of theiron metal during welding, and an arc preserving agent consisting of atleast about 90 per cent of magnesium incorporated in the coatedelectrode, for preventing extinction of the arc during welding.

2. A welding electrode for electric arc welding comprising a coreconsisting of at least about 50 percent of iron, a slag-forming coatingon said core, a reducing agent in said coating consisting of asufiicient percentage of material other than magnesium to preventoxidation of the iron metal during welding, and an arc preservingagent'consisting of at least about 90 per cent of magnesium incorporatedin the coated electrode in an amount of from about 0.5 to about 5 percent by weight of the coating, for preventing extinction of the arcduring welding.

3. A welding electrode for electric arc welding corporated, in the formof a separate layer interposed between said coating and said core, in anamount of from about 0.5 to about 3 percent by weight of the coating,for preventing'extinc tion of the arc during welding.

6. A welding electrode for electric arc welding comprising a coreconsisting of a metal selected from the group constituted by iron andiron alloys containing at least about" per cent of iron,

1 prevent oxidation of the iron metal during welding, and an arcpreserving agent consisting of at least about per cent of magnesiumincor-' porated in the coated electrode in an amount of from about 0.5to about 5 per cent by weight of the coating, for preventing extinctionof theiarc during welding.

'7. A welding electrode for electric arc-welding comprising a coreconsisting of a metal selected from the group constituted by iron andiron alloys containing at least about 50 per cent of'iron, aslag-forming coating on said core, a reducing agent in said coatingconsisting of asufiicient percentage of material selected from the groupconstituted by iron powder and iron-manganese, iron-silicon andiron-titanium alloys,'to prevent oxidation of the iron metal duringwelding, and an arc preserving agent consisting of at least about 90 percent of magnesium incorporated in the coated electrode in an amount offrom about 0.5 to about 5 per cent by weight of the coating, forpreventing extinction of the arc during welding.

' JOI-IANN DIEDRICH FAST.

